Paging systems are typically one way radio communication systems. An individual wishing to communicate with a pager user usually calls a central telephone number to access the central paging control. The central paging control can be either automatic or operated by a human operator. If automatic, the caller keys in the number assigned to the individual pager they wish to reach. Once that pager is accessed, the caller can either leave a voice message for the paged individual or key in the telephone number to be displayed on the pager's display. Some systems may also allow both types of paging.
If the central paging control is operated by a human operator, the caller typically tells the operator the number of the pager and the message. The operator then pages the individual, and relays the message when the paged individual calls the operator.
Once paged, the individual must find a telephone to answer the page. This problem can be solved by the paged individual carrying a cellular radiotelephone. The radiotelephone allows a mobile user to make or receive a call anywhere within an area covered by the cellular communications system antennas.
One problem with radiotelephone communication is that the radiotelephone user typically pays for incoming as well as outgoing calls. If an unwanted call is made to the radiotelephone, therefore, the radiotelephone user must pay for it at much higher rates than receiving a page. The pager, therefore, allows the called party to screen incoming calls to determine which telephone number to call back, thereby eliminating the charges for unwanted calls.
While the pager solves some of the limitations of the cellular radiotelephone and vice versa, this creates the problem of carrying two communication devices to remain in contact while moving about an area. There is a need therefore for a single device combining the advantages of both the cellular radiotelephone and the pager.